Nonlinear and bistable optical devices for use in computing and switching systems must have a low switching energy. A low switching energy allows many similar devices to be packed into a small volume for parallel processing, and also allows high speed switching to be implemented.
Nonlinear and bistable optical devices have in the past required a high switching energy. They have therefore relied upon the high gain of a high finesse optical cavity such as a Fabry Perot Cavity in order to reduce the switching energy needed for either nonlinear or bistable operation. A bistable optical device having a low switching energy is described by D. S. Chemia-D. A. B. Miller-P. W. Smith in U.S. patent application Ser. No. 566,968. The optical switching energy between bistable states opf the Chemla et al. device was somewhat greater than 100 femtojoules/square micron. However a high finesse Fabry Perot cavity was required in order to achieve this low value of the switching energy in the Chemla et al. device.